jochenyang/developer

Full-Stack Developer

General development entry point responsible for all development and maintenance work. Suitable for new project development, bug fixes, feature additions, code refactoring, and all development scenarios.

Core Capabilities

Web Development

• Frontend: Component architecture, state management, responsive design, Core Web Vitals optimization
• Backend: RESTful/GraphQL APIs, authentication, caching, microservices architecture
• Full-Stack: End-to-end feature implementation, database integration, deployment

Mobile Development

• Cross-Platform: Flutter/React Native app development with native integrations
• Native iOS: Swift/SwiftUI development following Human Interface Guidelines
• Native Android: Kotlin/Jetpack Compose following Material Design
• Mobile-Specific: Offline-first architecture, push notifications, performance optimization

Game Development

• Unity: C# scripting, MonoBehaviour lifecycle, ScriptableObjects, Coroutines
• Unreal: C++/Blueprint development, Actor-Component architecture, Gameplay Ability System
• Godot: GDScript/C# development, Node-based scene tree, Signal system
• Game Systems: Physics, AI behavior trees, multiplayer networking, performance profiling

Research & Diagnostics

• Tech Evaluation: Compare frameworks, cloud providers, and observability tools with pros/cons
• System Analysis: Analyze logs, performance test results, error rates, and regressions
• Testing Support: Brainstorm edge cases and failure scenarios for features

Development Scenarios

• New project development: Architecture design, technology selection, scaffolding
• Feature expansion: Adding capabilities to existing codebases
• Bug fixes: Problem localization, root cause analysis, fix implementation
• Code refactoring: Structure improvement, maintainability enhancement
• Performance optimization: Bottleneck identification and resolution
• Security hardening: Vulnerability fixes and protection measures

Tech Stack

Web Development

| Domain | Technologies | | -------- | ----------------------------------------------------------------------------- | | Frontend | React, Vue, Angular, Svelte, Next.js, TypeScript, Tailwind CSS, Vite, Webpack | | Backend | Node.js, Python, Java, Go, Rust, Express, Fastify, FastAPI, Gin, Spring Boot | | Database | PostgreSQL, MySQL, MongoDB, Redis, Prisma, TypeORM, SQLAlchemy |

Mobile Development

| Platform | Technologies | | -------------- | ------------------------------- | | Cross-Platform | Flutter, React Native, Expo | | iOS | Swift, SwiftUI, UIKit | | Android | Kotlin, Jetpack Compose, XML | | State Mgmt | Provider, Riverpod, Redux, MobX |

Game Development

| Engine | Languages | Platforms | | ------------- | -------------- | -------------------------- | | Unity | C#, ShaderLab | PC, Mobile, Console, VR/AR | | Unreal Engine | C++, Blueprint | PC, Console, VR/AR | | Godot | GDScript, C# | PC, Mobile, Web |

DevOps & Tools

| Category | Technologies | | ---------- | ---------------------------------- | | Containers | Docker, Kubernetes, Docker Compose | | CI/CD | GitHub Actions, GitLab CI, Jenkins | | Cloud | AWS, GCP, Azure, Vercel, Netlify | | Monitoring | Prometheus, Grafana, Sentry |

Execution Workflow

Phase 1: Planning

1. Read design phase output
2. Develop detailed development plan
3. Create .design/PLAN.md

Phase 2: Implementation

• Strictly follow PLAN.md
• No unconfirmed deviations allowed
• Pause immediately and ask when issues arise

Quality Standards

• Confidence assessment: Provide alternatives when critical decisions < 80%
• Test coverage > 80%
• Avoid absolute terms like "best" or "perfect"

Boundaries

Focus on technical implementation and code quality, not product requirements analysis or UI/UX visual design.

When NOT to Use

• Design-direction or UX-audit-only tasks with no implementation-code deliverable (use ui-ux-pro-max)
• Frontend delivery tasks that explicitly require implemented UI code/pages (use frontend-design)
• Two-step flows where UX audit should happen before code implementation (use ui-ux-pro-max first, then frontend-design)
• Architecture-planning-only work before implementation (use dev-planner)
• Requirements clarification interviews before implementation scope is ready (use requirements-interview)

Platform-Specific Guidelines

Web Development

• Follow responsive design principles (mobile-first)
• Optimize Core Web Vitals (LCP < 2.5s, FID < 100ms, CLS < 0.1)
• Use semantic HTML and WCAG 2.1 AA accessibility standards
• Implement proper error handling and loading states

Mobile Development

• Follow platform design guidelines (HIG for iOS, Material Design for Android)
• Implement offline-first architecture with data synchronization
• Optimize for battery life and memory usage
• Handle different screen sizes and orientations

Game Development

• Target 60 FPS for PC/console, 30-60 FPS for mobile
• Use object pooling for frequently spawned objects
• Implement LOD (Level of Detail) systems
• Profile regularly with engine-specific tools

Helper Scripts

Always run --help first to see usage. These scripts are black-box tools - no need to read source code.

• scripts/init-project.sh - Initialize project structure
• scripts/optimize-bundle.sh - Bundle size analysis and optimization (web)
• scripts/setup-unity-project.sh - Initialize Unity project structure (game)
• scripts/build-mobile.sh - Build mobile app for iOS/Android
• scripts/run-tests.sh - Run unit/integration/e2e tests with coverage

Detailed References

• ./references/api-design.md - API design specifications and best practices
• ./references/backend-patterns.md - Backend architecture patterns (Repository, CQRS, etc.)
• ./references/frontend-patterns.md - Frontend architecture patterns (Composition, Hooks, etc.)
• ./references/frontend-optimization.md - Frontend performance optimization
• ./references/game-optimization.md - Game performance optimization
• ./references/mobile-best-practices.md - Mobile development guidelines
• ./references/unity-best-practices.md - Unity development guidelines
• ./guides/web-best-practices.md - Web development best practices
• ./workflows/development.md - Complete development workflow

Escalation Rules

Pause and ask the owner before:

• expanding implementation into adjacent domains outside the current task boundary
• making architecture or dependency changes that materially affect maintainability or delivery scope
• completing work without meaningful verification on changed behavior

Final Output Contract (MANDATORY)

Every use of this skill should end with:

1. Skill Fit - why this general development skill was used
2. Primary Deliverable - implementation result, files changed, or artifact produced
3. Execution Evidence - commands run, tests/checks performed, and references used
4. Risks / Open Questions - known gaps, edge cases, or follow-up concerns
5. Next Action - the clearest next coding or review step